It is a combination of two planetary gear mechanisms (see the sketch).
Orange workpieces (here only one is shown) are moved by violet separator and slapped between two transparent grey slapping disks. The upper disk is forced down by springs (not shown).
Input 1: yellow cylinder to which an external and an internal gears are fixed.
Input 2: brown carrier to which a gear is fixed.
Input 3: blue shaft to which a gear is fixed.
Various motion rules are applied for the three inputs to get desired motion of the workpieces.